The photon is the ultimate unit of information because it packages data in a signal of zero mass and has unmatched speed. The power of light is driving the photonicrevolution, and information technologies, which were formerly entirely electronic, are increasingly enlisting light to communicate and provide intelligent control. Plasmonic nanophotonics promises to create entirely new prospects for guiding light on the nanoscale, some of which may have revolutionary impact on present-day optical technologies.

\“Electronics\” uses our ability to control electrons with electric fields via interaction with their fundamental charge. Because we can manipulate the electric fields within semiconductors, they are the basis for microelectronics, and silicon (Si)
is the most widely-used semiconductor for integrated microelectronic circuits. The electron\‘s magnetic moment, called
spin, has been known for over eighty years, and its existence explains (among other things) the static magnetic field of
permanent magnets. Our understanding of electron spin manipulation has led to information-storage applications such as
high-sensitivity magnetic field sensors for hard-drives (Giant Magneto-Resistance – or GMR – devices), and devices for
non-volatile random-access memory called Tunnel Magneto-Resistance (TMR) devices; however, it has not yet found use
in information-processing circuits. To enable spin-based integrated circuits, long spin lifetimes are necessary to enable
multiple logic operations before depolarization and decoherence sets in. In addition, long spin transport coherence lengths
are needed to enable integration of multiple devices in a circuit. Silicon has been broadly viewed as the ideal material for
spintronics due to its low atomic weight, lattice inversion symmetry, and near lack of nuclear spin. Despite this appeal,
however, the experimental difficulties of achieving coherent spin transport in silicon were overcome only recently (in our
lab here at Delaware), by using unique spin-polarized hot-electron injection and detection techniques with nano-scale ferromagnetic metal spin \“polarizers\”.1 Using these methods, we have observed unprecedented coherence in spin precession measurements, and extracted very long spin lifetimes of conduction electrons traveling over macroscopic distances.2 Whereas transistor scaling limits will soon suppress progress in microelectronics using Si, its favorable spintronics properties may secure this semiconductor\‘s dominance for the future.

I will discuss recent progress in experimental techniques to control the orientations of nanoscale magnetic moments and electron spins, and to use these new means of control for applications. One powerful new capability arises from the fact that thin magnetic layers can act as filters for spins.

First, I will discuss the physics and applications of 2D heterostructures composed of stacked monolayers of MoSe_2 and WSe_2 . These heterostructures host interlayer valley excitons where the electrons and holes are located in different layers. These spatially indirect excitons exhibit long lifetimes and valley polarization times which are promising for valley based information applications and for investigating long-range spin transport phenomena. Second, I will discuss single excitons localized to defects in monolayer WSe_2 , which are shown to be single photon emitters. I will discuss the physics of these localized quantum states as well as their potential quantum photonics applications....

In recent years, in my group we have been working on various aspects of metamaterials and plasmonic nano-optics. We have introduced and been developing the concept of \“metatronics\”, i.e. metamaterial-inspired optical nanocircuitry, in which the three fields of \“electronics\”, \“photonics\” and \“magnetics\” can be brought together seamlessly under one umbrella – a paradigm which I call the \“Unified Paradigm of Metatronics\”. In this novel optical circuitry, the nanostructures with specific values …